When storing hazardous materials in enclosures such as drums, convenience cans or even rooms, it is frequently necessary to vent gasses from the enclosures in order to avoid hazardous situations. Exemplary of gasses which should be vented from enclosures are hydrogen gas, and volatile organic compounds which can result in explosions if not vented. Of particular concern are transuranic materials which contain or generate hydrogen gas. There is a risk if hydrogen gas is not allowed to exit from a container that the gas will cause an explosion within the container dispersing radioactive materials into the surrounding environment.
Nuclear storage enclosures must be able to store a nuclear waste material for thousands of years without rupturing or leaking. Accordingly, venting hydrogen gas and volatile organic compounds is necessary for at least the initial portion of the storage period. Transuranic material frequently includes corrosive agents such as hydrochloric acid, nitric acid, 1,1,TCE and carbon tetrachloride which, over time, tend to corrode materials such as stainless steel used for drums and convenience cans. This is especially the case at locations within drums such as vents where stainless steel interfaces with filter media and fluid materials are flowing. More particularly, it is necessary to control VOC release and ventilation of hydrogen gas generated in 55-gallon drums, overpacked drums, and standard waste boxes containing TRU, low level hazardous or mixed wastes that contain chlorinated solvents, hydraulic acid or nitric acid.
Tests have indicated that the prior art filters such as sintered metal filters become plugged when HCl/CCl4 is bubbled therethrough so as to not permit passage of hydrogen gas. It was further found that 316 stainless steel housings with epoxy sealant and a carbon composite filter resulted in the epoxy becoming gooey due to reaction with solvents. It was further found that a mechanical press fit seal of a carbon-to-carbon composite filter in a 316 stainless steel housing passed compatibility tests with nitric acid, CCl4 and TCE with no change in filtration performance, however, this arrangement is not compatible with HCl because exposure to HCl results in the filter media becoming plugged with a corrosion residue that is moist with condensed acid fumes. Isolated carbon-to-carbon filter media exhibited no plugging when tested in the absence of adjacent stainless steel structure.